Abnormal Combustion of Two Stroke Cycle Gasoline Snowmobile Engine at High Speed and Full Load

Abnormal combustion, which is a cause for engine failure, is explicated to be high speed knocking by multi-cycle analysis of the cylinder pressure data of snowmobile two stroke cycle engines operated at high speed and wide open throttle condition.

A mini-computer was used for the analysis of the cylinder pressure data. Calculation of the entire cycle was conducted until an engine actually failed and the relationship between the engine failure and the conditions surrounding the knocking was made clear.

Using the rate of pressure change as a quantitative evaluation method for high speed knocking, a combustion chamber shape with less knocking occurrence possibility was selected.